At Real Simple, it’s part of our jobs to speak to experts on how to live better, easier, and more fulfilling lives. And perhaps nowhere is that more interesting than when it comes to the unique difficulty of maintaining a satisfying, healthy relationship long-term. Over the years, we’ve spoken to dozens of experts on what exactly makes happy couples tick. And while all of their advice is worth considering, we’ve distilled it down to the only 10 tips you really need to know.